US Open: Andy Murray Survives Scare, Backs New Rules to Cut Down Retirements

Andy Murray escaped his earliest US Open exit in 10 years on Thursday as the searing heat at Flushing Meadows took the number of men's singles retirements to a Grand Slam record 12.

Third seed and 2012 champion Murray came back from two sets down to defeat tiring Frenchman Adrian Mannarino 5-7, 4-6, 6-1, 6-3, 6-1 on Arthur Ashe Stadium.

Murray goes on to face Brazilian 30th seed Thomaz Bellucci for a place in the last 16.

"It was extremely tough. He hits the ball really flat, has fantastic timing on both sides and it was hard to read the ball in the first two sets," said 28-year-old Murray after his eighth career comeback from two sets to love down.

Murray, who had needed four sets to beat Nick Kyrgios in the opening round, fired 21 aces -- the last of which was on match point -- while Mannarino was undone by 61 unforced errors.

"When it's extremely hot and humid, it helps to have that break," said Murray of the 10-minute rest that women players take between the second and third sets when the temperature goes above 30.1 degrees.

"I don't know exactly what it's for. But I guess you get the chance to sort of go off and change, get under a cold shower if you want to."

"If someone's injured before they go out there, they're just going to play five games or a few games just to get the first-round cheque, then that's really bad for anyone that's paid to come and watch," he said.

"So the best thing to do, if you've worked the whole year to get into these events and earned the right to play, if you show up here and withdraw, give the lucky loser a chance.

"But the player that pulls out takes the first-round prize money. If I was the lucky loser, I'd be delighted to have the chance to play for the second-round prize money.

"I think the player that's earned the right to be there in the first place, you give them the first-round prize money and you avoid people walking on the court for a few games. It's a waste of time for everyone."

Meanwhile, America's Jack Sock and Denis Istomin retired from their matches as they wilted in the 33-degree Celsius (91.4 F) heat.

Twelve men -- a record at the majors -- as well as two women have quit matches in the first four days.

The 22-year-old Sock was leading Belgium's Ruben Bemelmans 6-4, 6-4, 3-6, 1-2 when he started cramping and was forced to retire.

Sock, the 28th seed, then collapsed on the court, where he was treated with ice packs and cold towels by US Open medical staff before being helped off to the shade of the Grandstand Court.

Bemelmans next plays fifth-seeded French Open champion Stan Wawrinka who beat South Korean teenager Hyeon Chung 7-6 (7/2), 7-6 (7/4), 7-6 (8/6).

Istomin also called it quits on Court Seven against Austrian 20th seed Dominic Thiem, who was 6-4, 6-4, 1-0 up at the time, with his win coming on his 22nd birthday.

The carnage led again to suggestions that the men, who play the best of five sets, should be accorded the same protection as women players.

The WTA allows a 10-minute break between the second and third sets of women's matches when the mercury bursts through 30.1 degrees.

"I honestly don't know what I want to see. I'm normally OK with heat and humidity," said Wawrinka.

"I don't have problem physically. Never retired because of that. Never had really big cramping or big problem because of that.

"For me, it's fine. I'm still OK with no rule."

Britain's world number 97 Johanna Konta made history when she defeated Wimbledon runner-up Garbine Muguruza in the longest women's match in US Open history, which was played at the hottest time of the day on Court 17.

"I thought it would be really embarrassing if I just toppled over there," said Konta, who won 7-6 (7/4), 6-7 (4/7), 6-2 in 3 hours 23 minutes.

"It's a horrible situation to be in."

It beat by seven minutes the previous record set in 2011 when Samantha Stosur defeated Nadia Petrova.

Sydney-born Konta has now won 15 matches in a row since Wimbledon and goes on to tackle German 18th seed Andrea Petkovic for a place in the last 16.

Muguruza committed 59 unforced errors and had to save 15 of 19 break points.

Ninth seeded Muguruza became the fifth top-10 seed to crash out of this year's tournament before the third round.

With Maria Sharapova having withdrawn through injury on the eve of the season's concluding Grand Slam, the women's draw was down to its bare bones.

Top seed Serena Williams made the last 32 on Wednesday and was joined Thursday by second seed Simona Halep and fifth-seeded Petra Kvitova.

Halep advanced by defeating Ukraine's 104th-ranked Kateryna Bondarenko 6-3, 6-4 and next plays American Shelby Rogers.

Fifth seed and two-time Wimbledon champion Petra Kvitova saw off Nicole Gibbs of the United Stares 6-3, 6-4.

Australian 22nd seed Stosur, the last woman to beat Serena Williams at the US Open four years ago when she took the title, breezed past Russia's Evgeniya Rodina -- one of two mothers to have reached the second round -- 6-1, 6-1.

Stosur, 31, fired eight aces with no double faults and hit 29 winners in her quick-fire win, which gave her a third-round encounter against Italian 16th seed Sara Errani.

Despite the victory, Stosur hit out at organisers, who she claims have blundered over transport for players as well as practice court arrangements.

Stosur said she was forced to switch courts on Wednesday when Williams needed a place to practice.

"She kicked me off my practice court yesterday...so a few issues," claimed the Australian.